Glyphosate, a type of organophosphate with the molecular structure shown below, has been widely used as a herbicide, and subsequently has entered into waterways and the drinking water supply:

However, even at an ultra-dilute concentrations (about 1 part per million (ppm) to about 1 part per billion (ppb)), glyphosate has been found to damage the environment. Since glyphosate has a low molecular weight, high solubility in water, and a relatively long half-life, removing ultra-dilute glyphosate from water can be challenging using conventional filtration techniques.
For example, current approaches for removing glyphosates include chlorination, ozonation, membrane filtration, UV irradiation and adsorption onto various materials, which can be employed either separately or in combination. However, these removal techniques are slow and can be relatively expensive.
UV irradiation and ozonation break down glyphosate to small molecules, and the extent to which this degradation is complete depends on both the length of contact time and initial concentration of the glyphosate. Incomplete molecular degradation from UV irradiation and ozonation can form smaller molecules (e.g., aminomethyl phosphonic acid), which can potentially be more damaging to the environment than glyphosate. Thus, to ensure full removal of the glyphosate and its byproducts, the contact time of the contaminated water and the UV or ozonation system should be on the order of hours, which makes these processes unacceptable for commercial processes with short production times.
Activated carbon is another frequently used method for water purification that can be ineffective in reliably removing glyphosate from a solution such as water. While humic acids, clays and other natural materials can also be used for glyphosate removal, high salt concentrations in the water can reduce their efficiency. Humic acids, clays and other natural materials can also foul membranes used in purification processes.